In recent years, a magnetic head shifts from a magnetic head utilizing a giant magneto-resistive (GMR) effect toward a magnetic head utilizing a tunnel magneto-resistance (TMR) effect and the densification of a surface recording density advances rapidly in order to correspond to the increase in capacity of a hard disk drive. In accordance with the densification of a surface recording density, a magnetic head used in a hard disk drive is required to be miniaturized and a microprocessing technology is required in the production of a magnetic head. In a manufacturing apparatus of a magnetic head therefore, the shift from the application of an ion milling device to the application of a plasma etching device advances.
A magnetic head has a magnetic pole layer to generate a recording magnetic field for recording information on a recording medium by a perpendicular magnetic recording method and a containing layer to contain it and the groove part of the containing layer is formed into a tapered shape. Further, the containing layer has heretofore comprised an alumina (Al2O3) film but in recent years magnetic materials such as iron (Fe), ferronickel (NiFe), ferrocobalt (CoFe), and cobalt nickel iron (CoNiFe) are adopted in accordance with the reduction of the number of processes at a containing layer forming process.
Each of the magnetic materials however has a very low volatility, hence can hardly obtain an etching speed and a perpendicular shape by plasma, and can hardly be subjected to microprocessing. Further, a reaction product generated during plasma etching tends to adhere to the internal wall of a plasma processing chamber and change plasma etching performance with the lapse of time.
As a plasma etching method enabling reactive ion etching to such a magnetic material, a dry etching method of using a carbon monoxide (CO) gas to which a nitrogen compound contained gas such as an ammonia (NH3) or amine gas is added as a reaction gas is disclosed in Japanese Patent Application Laid-Open Publication No. H8-253881 for example.
Further, as a plasma etching method having a high selectivity of a material to be etched to a mask with a mixed gas of a nitrogen compound contained gas and a carbon monoxide gas, a method of carrying out etching by using the carbon monoxide gas to which the nitrogen compound contained gas is added as a reaction gas and a mask of tantalum or tantalum nitride is disclosed in Japanese Patent Application Laid-Open Publication No. 2001-274144.